6.2.0 build failure on x86_64 Skylake PC - FIX

[Marc Glisse]

On Sat, 30 May 2020, tsurzin wrote:

> This change worked to build test and run a version of GMP-6.2.0 for my PC.

[handle *-*-msys exactly the same as *-*-mingw* in configure.ac]

> The PC is running Msys2 under Windows 10 and without change GMP failed 
> to build.

configfsf.guess does mention a triple *-pc-msys, so I guess it makes sense 
to handle it (or replace it with something we already handle). I don't 
really know in what ways it differs from mingw, probably not that much as 
far as GMP is concerned.

I notice in a generated file:

aclocal.m4:      *-*-mingw* ) # actually msys

Should automake also be taught about the msys triple?

-- 
Marc Glisse